1. Field of the Invention
This invention relates to an assembly for packaging a discontinuously supplied stream of products, comprising a packaging apparatus provided with a carrier for rotatably supporting a roll containing a continuous packaging web, means for placing products to be packaged on the continuous packaging web, folding means for folding the longitudinal edges of the continuous packaging web around the products in longitudinal direction to form a tubular packaging sleeve, connecting means for forming in each case at least one transverse connection in the tubular packaging sleeve between two successive products, and separating means for breaking the tubular packaging sleeve in a transverse direction between the products for forming separated packaged products.
2. Description of Related Art
For packaging, for instance, newspapers, magazines or like documents in film or paper, use can be made of packaging machines as marketed by applicant. When being fed into the packaging apparatus, the products are first positioned on the continuous packaging web by means for placing products to be packaged. To that end, see applicant""s earlier patent application EP-A-0 685 417, whose subject matter is to be considered inserted herein Thereafter, by means of folding means, the longitudinal edges of the continuous web of film or paper are folded in a continuous manner around the products to be packaged. For a further elaboration of possible folding means, reference is made to applicant""s earlier patent application EP-A-0 686 555, whose subject matter is to be considered inserted herein. Thereafter, the continuous film or paper web with the longitudinal edges folded over, is cut through between the products and optionally sealed. To that end, see, for instance, applicant""s earlier patent application EP-A-0 689 994, whose subject matter is to be considered inserted herein. If too long an interruption in the supply of the products occurs, folding over the longitudinal edges may present problems as the longitudinal edges are not folded around anything: the products are lacking. When the interruption in the product stream is only one to four products long, most packaging machines of the above-mentioned type can still continue to function properly. However, when longer interruptions in the product stream occur, it is inevitable that failures occur in the packaging machine. Such a failure leads to a halt of the entire process upstream and the entire process downstream of the packaging machine. The upstream process can comprise, for instance, a printing process for newspapers. The downstream process can be formed, for instance, by a stacking/bundling process for bundling the packaged newspapers.
The most obvious solution to the above-described problems would naturally be to stack the products that are being supplied in the discontinuous product stream. After stacking, the products could successively be pulled from the stack to create a continuous product stream suitable for processing in the packaging machine. Such a stacking/unstacking assembly might perhaps be a remedy in the case of single products, such as, for instance, magazines. In the case of multilayer products, such as, for instance, a newspaper composed of a number of loose sections, such a solution is not possible, at least not in a simple manner, taking into account that the assembly according to the invention should be capable of processing at least about 20,000 products per hour. In itself, stacking and unstacking products at a rate of 20,000 to 40,000 items per hour is already a major problem, let alone stacking and unstacking multilayer products at such a rate. Accordingly, applicant has already described a solution to this problem in international patent application WO99/44925.
The object of the invention is to provide an alternative solution to the above-described problems.
To that end, the assembly of the type described in the preamble is characterized, according to the invention, in that the assembly comprises a feeding conveyor operatively supplying a discontinuous product stream, the assembly further comprising an intermediate conveyor for supporting and conveying products, the intermediate conveyor being built up from a number of mutually aligning conveying sections, the feeding conveyor being disposed with respect to the intermediate conveyor such that the delivery of the products by the feed conveyor occurs on an in-feed end of the intermediate conveyor, while the conveying sections of the intermediate conveyor are drivable independently of each other, and a discharge end of the intermediate conveyor links up with the means for placing products to be packaged on the continuous packaging web, the assembly, or at least the intermediate conveyor, being provided with a control adapted to drive the various conveying sections of the intermediate conveyor such that the mutual distances between discontinuously supplied products are reduced to a standard distance.
With such an assembly, a discontinuous stream can be condensed to a continuous stream of products which can be processed by the packaging apparatus without any problems.
By the assembly according to the invention, a discontinuous product stream of a capacity of about 20,000 to 40,000 products per hour can be processed and even be condensed to a continuous product stream. Such a capacity can even be achieved with products built up from several layers, such as, for instance, newspapers including a number of sections loosely overlying each other. A conveyor comprising several conveying sections each drivable independently of each other is described, for instance, in Dutch patent application NL-A-1004696. The subject matter of that patent application is to be considered inserted herein.
According to a further elaboration of the invention, the feeding conveyor can comprise a conveyor chain which is provided with grippers for clamping therein the products to be conveyed, the conveyor chain extending partly above an in-feed end of the intermediate conveyor, while the grippers are arranged for releasing the products above the in-feed end of the intermediate conveyor.